Presta valve problems?

As a rule I get very few flats. Never any pinch flats, despite the fact that I'm no lightweight. Two flats in the same week, one just before a century ride, have got me thinking about the flats I have gotten, and most of them seem to arise from defect in the tubes, not from road hazards.

More recently, the valve core came out when I took disconnected the pump head from the tire. Rear tire, with a group start on a century less than an hour away. The other day I got what seemed to be a "normal" flat, but when I took it to the lbs they found nothing in the tire, and just replaced what was apprently a faulty tube in the front tire.

What can I do to minimize this? To anticipate some questions, I've used a variety of brand tubes--Sepcialized, Performance, Nashbar--, and the flats seem evenly distributed between front and rear tires. I do use the screw on doohickeys that hold the stem in place in the rim, and valve caps.

Since there's no replacement for Presta tubes anytime soon, how can I maximize their lifespan, and might it be my fault and not the tubes or valves?

Some silver ones, a black one, a red one, an orange one and a couple of titanium ones

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Originally Posted by bernmart

As a rule I get very few flats. Never any pinch flats, despite the fact that I'm no lightweight. Two flats in the same week, one just before a century ride, have got me thinking about the flats I have gotten, and most of them seem to arise from defect in the tubes, not from road hazards.

More recently, the valve core came out when I took disconnected the pump head from the tire. Rear tire, with a group start on a century less than an hour away. The other day I got what seemed to be a "normal" flat, but when I took it to the lbs they found nothing in the tire, and just replaced what was apprently a faulty tube in the front tire.

What can I do to minimize this? To anticipate some questions, I've used a variety of brand tubes--Sepcialized, Performance, Nashbar--, and the flats seem evenly distributed between front and rear tires. I do use the screw on doohickeys that hold the stem in place in the rim, and valve caps.

Since there's no replacement for Presta tubes anytime soon, how can I maximize their lifespan, and might it be my fault and not the tubes or valves?

Prestas are pretty robust and not that easy to damage. When you take the pump head off, do you bend or twist the head to get it off? That's the way to bend the valve stem. As for flats, that's just a way of life. Check the tire for debris after a flat. The material that caused the flat may still be embedded in the tire and just lead to further flats. Try inspecting the tire from the outside too since the pokey bit may have pulled back into the casing.

You may also have something in the rim that is causing the flat. I had a bike that was plagued by flats but I could never find the cause. It turned out to be a small metal shaving in the rim strip.

Another trick is to alway put the tube into the tire in the same way. Line the valve stem up with the tire label and make the tube with left or right and always put it back the same way. If there is something that is causing flat after flat, this will help you track it down.

Good advice above. Some other things I do is buy tubes with no threads on the stem. This reduces friction on the stem and reduces the possibility of damaging the tube at the base of the stem. It also reduces damage to the "O" ring in the pump chuck. The only reason to use a stem lockring is to keep the stem from rocking back and forth when using a frame pump. That is one of the reasons I use CO2 on the road.
I always analyze flats until I know the cause.
I use Velox rim tape on all rims.
I pump my tires with a floor pump just before each ride.